The purpose of this project is to study the microbial flora of cancer patients. Surveillance cultures taken from these patients provide a means to monitor the flora and its acquisition. Clinically important strains are subspeciated by means of serotyping, phagetyping, etc. An unusual coryneform bacterium, which was recovered from 20 patients at the BCRC, was studied extensively. This organism was gram positive, non-motile and found to be resistant to all antibiotics tested with the exception of vancomycin, occasionally rifampin, and rarely erythromycin. Group D streptococci were evaluated from surveillance cultures, urine cultures and other sources. Order of prevalence for the various species was established and susceptibilities determined. A study of Serratia marcescens was undertaken; 10% of the 1314 patients admitted to BCRC between 9/72 and 1/77 had this organism recovered from their samples. The chief source of S. marcescens was found to be fresh uncooked foods and moist environmental areas. Advances in Staphylococcal phage typing made possible the detection of heavy shedding by mycosis fungoides patients colonized with S. aureus. Since then, isolation procedures are initiated when necessary.